The patent, first filed in 2008, proposes using skin-contacting sensors in earbuds or earphones to monitor body temperature, heart rate, and perspiration, though the patent doesn't outline the mechanics of how such sensors would work. It also suggests accelerometers, both for activity tracking and for a possible hands-free gesture control, where you could change tracks or adjust volume with a specific head motion.

The patent also makes passing mention of "psychological" sensors. The official filing doesn't expand on what this would mean or how it could be used, but AppleInsider speculates the system could analyse biometric input to get an impression of the user's mental state. Finally, headphones that know to queue up Adele when you need a good cry.

Standard patent skepticism most definitely applies here: Apple filing a patent is not any sort of guarantee that the company will actually make the proposed ear monitors. But the idea is pretty fascinating—putting biosensors into the headphones so many of us wear while exercising makes a tonne of sense.